This invention relates generally to the digital data decoding systems, and more particularly, to the use of such systems with compressed input from various sources beyond a base network connection.
Full motion video displays based upon digital video signals are becoming more widely available. While these displays have many advantages, they also often require massive amount of raw digital data. The transmission of these massive amounts of video information is often impractical or infeasible. For this reason, digital video signals are often compressed before being transmitted.
Various video compression standards or processes have been established, including MPEG-1 and MPEG-2. These conventional video compression techniques utilize similarities between successive image frames, referred to as temporal or interframe correlation, to provide interframe compression in which pixel based representations of image frames are converted to motion representations. In addition, the conventional video compression techniques use similarities within image frames, referred to as spatial or intraframe correlation, to provide intraframe compression in which the motion representations within an image frame are further compressed.
After the video data is compressed, or encoded, it is transmitted to a decoder that decodes, or decompresses, the compressed data to reconstruct the original video data. That data may then be shown on a video display device, such as a conventional television. Decoders that are used with television sets are often referred to as set-top box (STB) systems.
Stand-alone audio/video decoders currently used in set-top box systems generally utilize a dedicated interface to a specific transport chip and/or network interface module (NIM). As the required utility of these STB systems expands, it is becoming desirable to adopt compressed input from various sources in addition to the base network (cable/satellite) connection. These additional sources could be, for example, a local digital video disc (DVD) player or an internet connection. Oftentimes, this is accomplished by providing a feedthrough path from the application processor in this same interface, allowing the processor to directly load this data. However, this method has the possibility of being relatively slow and may require a significant portion of the processor bandwidth.
As the integration of audio/video decoders and other components of STB systems onto common silicon progresses, new options become viable. Integration allows greater flexibility in the interconnection of functional units and access to memory, such as a common memory subsystem architecture.